Global observation of iodic acid (HIO3)

2020 ◽  
Author(s):  
Xucheng He ◽  
Tuija Jokinen ◽  
Nina Sarnela ◽  
Lisa Beck ◽  
Heikki Junninen ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Cloud Condensation Nuclei ◽  
Particle Formation ◽  
Radiation Balance ◽  
Forest Site ◽  
Polar Regions ◽  
Aerosol Formation ◽  
Iodic Acid ◽  
Direct Role ◽  
Catalytic Ozone Destruction

<p>Trace iodine vapours have a significant impact on atmospheric chemistry, influencing catalytic ozone destruction and the HO<sub>x</sub> / NO<sub>x</sub> cycles. Oxidized iodine species also form aerosols in coastal and polar regions (O’Dowd et al, 2002), playing a direct role in Earth’s radiation balance. It was recently shown that iodic acid (HIO<sub>3</sub>) has a significant impact on coastal new particle formation processes (Sipilä et al., 2016). However, neutral HIO<sub>3 </sub>molecules have only been measured in two sites (Sipilä et al., 2016).</p><p>In this study, a global observation of HIO<sub>3</sub> has been carried out in ten sites around the globe, including city sites, Arctic and Antarctica sites, a remote island site, a coastal site and a boreal forest site. While the existence of HIO<sub>3</sub> is unambiguously revealed in all of the sites, its concentration varies significantly among them. Dedicated laboratory experiments are required to examine the particle formation rates from iodine-containing species to be able to predict their global importance in particle formation, and further, in cloud condensation nuclei formation.</p><p> </p><p>O’Dowd, C. D. et al. Marine aerosol formation from biogenic iodine emissions. Nature <strong>417</strong>, 632–6 (2002)</p><p>Sipilä, M. et al. Molecular-scale evidence of aerosol particle formation via sequential addition of HIO<sub>3</sub>. Nature <strong>537</strong>, 532–534 (2016).</p><p> </p>

scholarly journals Particle concentration and flux dynamics in the atmospheric boundary layer as the indicator of formation mechanism

2011 ◽  
Vol 11 (12) ◽  
pp. 5591-5601 ◽  
Author(s):  
J. Lauros ◽  
A. Sogachev ◽  
S. Smolander ◽  
H. Vuollekoski ◽  
S.-L. Sihto ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Formation Mechanism ◽  
Turbulent Transport ◽  
Particle Formation ◽  
Formation Mechanisms ◽  
Forest Site ◽  
Aerosol Formation ◽  
Flux Dynamics ◽  
Layer Deposition

Abstract. We carried out column model simulations to study particle fluxes and deposition and to evaluate different particle formation mechanisms at a boreal forest site in Finland. We show that kinetic nucleation of sulphuric acid cannot be responsible for new particle formation alone as the simulated vertical profile of particle number concentration does not correspond to observations. Instead organic induced nucleation leads to good agreement confirming the relevance of the aerosol formation mechanism including organic compounds emitted by the biosphere. The simulation of aerosol concentration within the atmospheric boundary layer during nucleation event days shows a highly dynamical picture, where particle formation is coupled with chemistry and turbulent transport. We have demonstrated the suitability of our turbulent mixing scheme in reproducing the most important characteristics of particle dynamics within the boundary layer. Deposition and particle flux simulations show that deposition affects noticeably only the smallest particles in the lowest part of the atmospheric boundary layer.

Studying new particle formation from chemical emissions from sea surface using  ship-borne air-sea-interaction tanks

2021 ◽  
Author(s):  
Maija Peltola ◽  
Manon Rocco ◽  
Neill Barr ◽  
Erin Dunne ◽  
James Harnwell ◽  
...  
Keyword(s):  
Marine Biology ◽  
Cloud Condensation Nuclei ◽  
Aerosol Particles ◽  
Chemical Species ◽  
Particle Formation ◽  
Biological Properties ◽  
The European Union ◽  
New Particle Formation ◽  
Aerosol Formation ◽  
Horizon 2020

<p>Even though oceans cover over 70% of the Earth’s surface, the ways in which oceans interact with climate are not fully known. Marine micro-organisms such as phytoplankton can play an important role in regulating climate by releasing different chemical species into air. In air these chemical species can react and form new aerosol particles. If grown to large enough sizes, aerosols can influence climate by acting as cloud condensation nuclei which influence the formation and properties of clouds. Even though a connection of marine biology and climate through aerosol formation was first proposed already over 30 years ago, the processes related to this connection are still uncertain.</p><p>To unravel how seawater properties affect aerosol formation and to identify which chemical species are responsible for aerosol formation, we built two Air-Sea-Interaction Tanks (ASIT) that isolate 1000 l of seawater and 1000 l of air directly above the water. The used seawater was collected from different locations during a ship campaign on board the R/V Tangaroa in the South West Pacific Ocean, close to Chatham Rise, east of New Zealand. Seawater from one location was kept in the tanks for 2-3 days and then changed. By using seawater collected from different locations, we could obtain water with different biological populations. To monitor the seawater, we took daily samples to determine its chemical and biological properties.</p><p>The air in the tanks was continuously flushed with particle filtered air. This way the air had on average 40 min to interact with the seawater surface before being sampled. Our air sampling was continuous and consisted of aerosol and air chemistry measurements. The instrumentation included measurements of aerosol number concentration from 1 to 500 nm and  chemical species ranging from ozone and sulphur dioxide to volatile organic compounds and chemical composition of molecular clusters.</p><p>Joining the seawater and atmospheric data together can give us an idea of what chemical species are emitted from the water into the atmosphere and whether these species can form new aerosol particles. Our preliminary results show a small number of particles in the freshly nucleated size range of 1-3 nm in the ASIT headspaces, indicating that new aerosol particles can form in the ASIT headspaces. In this presentation, we will also explore which chemical species could be responsible for aerosol formation and which plankton groups could be related to the emissions of these species. Combining these results with ambient data and modelling work can shed light on how important new particle formation from marine sources is for climate.</p><p>Acknowledgements: Sea2Cloud project is funded by European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant agreement No. 771369).</p>

scholarly journals Modelling the formation of organic particles in the atmosphere

2003 ◽  
Vol 3 (6) ◽  
pp. 6147-6178 ◽  
Author(s):  
T. Anttila ◽  
V.-M. Kerminen ◽  
M. Kulmala ◽  
A. Laaksonen ◽  
C. O’Dowd
Keyword(s):  
Sulphuric Acid ◽  
Particle Formation ◽  
Water Soluble ◽  
Forest Site ◽  
Initial Growth ◽  
Aerosol Formation ◽  
Stable Clusters ◽  
Kohler Theory ◽  
Organic Particles ◽  
Organic Particle

Abstract. A modelling study investigating the formation of organic particles from inorganic, thermodynamically stable clusters was carried out. A recently-developed theory, the so-called nano-Köhler theory, which describes a thermodynamic equilibrium between a nanometer-size cluster, water and water-soluble organic compound, was implemented in a dynamical model along with a treatment of the appropriate aerosol and gas-phase processes. The obtained results suggest that both gaseous sulphuric acid and organic vapours contribute to organic particle formation. The initial growth of freshly-nucleated clusters having a diameter around 1 nm is driven by condensation of gaseous sulphuric acid and by a lesser extent cluster self-coagulation. After the clusters have reached sizes of around 2 nm in diameter, low-volatile organic vapours start to condense spontaneously into the clusters, thereby accelerating their growth to detectable sizes. A shortage of gaseous sulphuric acid or organic vapours limit, or suppress altogether, the particle formation, since freshly-nucleated clusters are rapidly coagulated away by pre-existing particles. The obtained modelling results were applied to explaining the observed seasonal cycle in the number of aerosol formation events in a continental forest site.

scholarly journals Determination of the absorption cross sections of higher-order iodine oxides at 355 and 532 nm

2020 ◽  
Vol 20 (18) ◽  
pp. 10865-10887
Author(s):  
Thomas R. Lewis ◽  
Juan Carlos Gómez Martín ◽  
Mark A. Blitz ◽  
Carlos A. Cuevas ◽  
John M. C. Plane ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Atmospheric Chemistry ◽  
Absorption Cross Section ◽  
Particle Formation ◽  
Absorption Cross ◽  
Iodic Acid ◽  
Iodine Oxides ◽  
532 Nm

Abstract. Iodine oxides (IxOy) play an important role in the atmospheric chemistry of iodine. They are initiators of new particle formation events in the coastal and polar boundary layers and act as iodine reservoirs in tropospheric ozone-depleting chemical cycles. Despite the importance of the aforementioned processes, the photochemistry of these molecules has not been studied in detail previously. Here, we report the first determination of the absorption cross sections of IxOy, x=2, 3, 5, y=1–12 at λ=355 nm by combining pulsed laser photolysis of I2∕O3 gas mixtures in air with time-resolved photo-ionization time-of-flight mass spectrometry, using NO2 actinometry for signal calibration. The oxides selected for absorption cross-section determinations are those presenting the strongest signals in the mass spectra, where signals containing four iodine atoms are absent. The method is validated by measuring the absorption cross section of IO at 355 nm, σ355nm,IO= (1.2±0.1) ×10-18 cm2, which is found to be in good agreement with the most recent literature. The results obtained are σ355nm,I2O3<5×10-19 cm2 molec.−1, σ355nm,I2O4= (3.9±1.2)×10-18 cm2 molec.−1, σ355nm,I3O6= (6.1±1.6)×10-18 cm2 molec.−1, σ355nm,I3O7= (5.3±1.4)×10-18 cm2 molec.−1, and σ355nm,I5O12= (9.8±1.0)×10-18 cm2 molec.−1. Photodepletion at λ=532 nm was only observed for OIO, which enabled determination of upper limits for the absorption cross sections of IxOy at 532 nm using OIO as an actinometer. These measurements are supplemented with ab initio calculations of electronic spectra in order to estimate atmospheric photolysis rates J(IxOy). Our results confirm a high J(IxOy) scenario where IxOy is efficiently removed during daytime, implying enhanced iodine-driven ozone depletion and hindering iodine particle formation. Possible I2O3 and I2O4 photolysis products are discussed, including IO3, which may be a precursor to iodic acid (HIO3) in the presence of HO2.

Composition and concentrations of aerosol precursor gases in the sub-Arctic boreal forest

2021 ◽  
Author(s):  
Tuija Jokinen ◽  
Katrianne Lehtipalo ◽  
Kimmo Neitola ◽  
Nina Sarnela ◽  
Totti Laitinen ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Sulfuric Acid ◽  
Ambient Air ◽  
Particle Formation ◽  
The Arctic ◽  
New Particle Formation ◽  
Aerosol Formation ◽  
Iodic Acid ◽  
Field Station

&lt;p&gt;One way to form aerosol particles is the condensation of oxidized atmospheric trace gases, such as sulfuric acid (SA) into small molecular clusters. After growing to larger particles by condensation of low volatile gases, they can affect the planets climate directly by scattering light and indirectly by acting as cloud condensation nuclei. Observations of low-volatility aerosol precursor gases have been reported around the world but long-term measurement series and Arctic data sets showing seasonal variation are close to non-existent. In here, we present ~7 months of aerosol precursor gas measurements performed with the nitrate based chemical ionization mass spectrometer (CI-APi-TOF). We deployed our measurements ~250 km above the Arctic Circle at the Finnish sub-Arctic field station, SMEAR I in V&amp;#228;rri&amp;#246;. We report concentration measurements of the most common new particle formation related compounds; sulfuric acid, methanesulfonic acid (MSA), iodic acid (IA) and highly oxygenated organic compounds, HOMs. At this remote measurement site, surrounded by a strict nature preserve, that gets occasional pollution from a Russian city of Murmansk, SA is originated both from anthropogenic and biological sources and has a clear diurnal cycle but no significant seasonal variation, while MSA as an oxidation product of purely biogenic sources is showing a more distinct seasonal cycle. Iodic acid concentrations are the most stable throughout the measurement period, showing almost identical peak concentrations for spring, summer and autumn. HOMs are abundant during the summer months and due to their high correlation with ambient air temperature, we suggest that most of HOMs are products of monoterpene oxidation. New particle formation events at SMEAR I happen under relatively low temperatures, low relative humidity, high ozone concentration, high SA concentration in the morning and high MSA concentrations in the afternoon. The role of HOMs in aerosol formation will be discussed. All together, these are the first long term measurements of aerosol forming precursor from the sub-arctic region helping us to understand atmospheric chemical processes and aerosol formation in the rapidly changing Arctic.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

Observations of New Particle Formation events during summertime in Helsinki

2021 ◽  
Author(s):  
Roseline Thakur ◽  
Lubna Dada ◽  
Lisa Beck ◽  
Tommy Chan ◽  
Juha Sulo ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Urban Areas ◽  
Boreal Forests ◽  
Cloud Condensation Nuclei ◽  
Cyanobacterial Bloom ◽  
Particle Formation ◽  
Capital City ◽  
Atmospheric Conditions ◽  
New Particle Formation ◽  
Iodic Acid

&lt;p&gt;Aerosols can originate from different sources and undergo various formation pathways. New Particle formation (NPF) events occur when precursor vapors nucleate and vapors with low volatility condense on the critical nuclei enabling them to grow to cloud condensation nuclei (CCN) relevant sizes. As CCN, these aerosols affect the occurrence of clouds and their lifetime on local, regional and global level. &amp;#160;Many studies have investigated new particle formation events from various sites ranging from urban areas, boreal forests to pristine locations; however, there is still a dearth of studies investigating coastal new particle formation, which is a complex phenomenon due to the dynamic and ever-changing atmospheric conditions at the coast.&amp;#160; A comprehensive study of particle number distributions and aerosol forming precursor vapors was carried out in a coastal capital city of Finland, Helsinki, during the summer of 2019. The experimental setup comprising of a nitrate-based chemical ionization atmospheric pressure interface time of flight mass spectrometer (CI-APi-TOF), a neutral cluster-air ion spectrometer (NAIS) and a particle size magnifier (PSM) were housed in and around the SMEAR III station in Kumpula Science campus. SMEAR III is a unique site situated in a semi-urban yet coastal location. The period of experiment coincided with the cyanobacterial bloom in the coastal areas of Finland and in the Baltic Sea region. Our study recorded several regional NPF and aerosol burst events during this period. High concentrations of sulfuric acid was found to be associated with the regional NPF events whereas increasing iodic acid concentrations was mostly associated with the initiation of burst events. The sources of sulfuric acid and iodic acid has been carefully evaluated in this study.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

Studies of the connection between condensable trace gases and aerosol particles in Svalbard

2021 ◽  
Author(s):  
Tuuli Lehmusjärvi ◽  
Roseline Thakur ◽  
Lisa Beck ◽  
Mikko Sipilä ◽  
Tuija Jokinen
Keyword(s):  
Cloud Condensation Nuclei ◽  
Regional Climate ◽  
High Arctic ◽  
Particle Formation ◽  
Urban Environments ◽  
The Arctic ◽  
New Particle Formation ◽  
Iodic Acid ◽  
Summer Time

&lt;p&gt;In the high Arctic, the climate is warming faster than in the lower latitudes due to the Arctic amplification. Sea ice is melting and permafrost is thawing, and the scarce vegetation of the Arctic is changing rapidly. All these varying conditions will have an impact on possible emission sources of aerosol precursor gases, thus affecting the New Particle Formation (NPF) in the Arctic atmosphere, of which we still know very little. It is important to study the NPF events, which parameters affect the aerosol phase and how these newly formed aerosols can grow into cloud condensation nuclei sizes. Only then, it is possible to understand how climate change is affecting the aerosol population, clouds and regional climate of the pristine Arctic. The role of the precursor gases like Sulphuric Acid (SA), Iodic Acid (IA), Methane Sulphonic Acid (MSA) and Highly Oxygenated organic Molecules (HOM) in NPF in boreal and urban environments has been explored to a great extent. However, the role of these precursor gases in NPF events in remote locations - devoid of pollution sources and the vegetation - is still ambiguous. Therefore, it is crucial to conduct long-term measurements to study the composition and concentrations of aerosol precursors molecules, nanoparticles and air ions in remote and climatically fragile place like Ny-&amp;#197;lesund in the Arctic. This research location is not only a natural pristine laboratory to understand the atmospheric processes but also acts as a climate mirror reflecting the most drastic changes happening in the atmosphere and cryosphere. In this study, we aim to enhance the understanding of the role of aerosol precursor gases in new particle formation in Ny-&amp;#197;lesund, Svalbard.&lt;/p&gt;&lt;p&gt;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160; We have studied aerosol particle formation now for almost three years in the Ny-&amp;#197;lesund research village in Svalbard (78&amp;#176; 55' 24.7368'' N, 11&amp;#176; 54' 35.6220'' E.) with the Neutral cluster and Air Ion Spectrometer (NAIS) measuring ~1-40 nm particles and ions. We have conducted measurements with a Chemical Ionization Atmospheric Pressure interface Time Of Flight (CI-APi-TOF) mass spectrometer to understand the chemical composition of organic precursors vapours and abundance of inorganic aerosol precursor gases such as SA, MSA and IA. Additionally, &amp;#160;we have studied the emission and composition of volatile organic compounds on the site during summer-time.&lt;/p&gt;&lt;p&gt;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160; In this study, we report the time series concentrations of the most common aerosol precursor gases like SA, MSA, IA and HOM from the period 28.6.-25.7.2019, which are responsible for the initiation and/or growth of particles. The variability in the concentrations of these vapours is compared between NPF event and non-event days. The study explores also the role of meteorological parameters like wind speed, wind direction, temperature and humidity on NPF processes.&lt;/p&gt;

Composition and Properties of the Natural Aerosol over the Boreal and Tropical Forests

2020 ◽  
Author(s):  
Hans-Christen Hansson ◽  
Paulo Artaxo ◽  
Meinrat Andreae ◽  
Markku Kulmala
Keyword(s):  
Tropical Forests ◽  
Atmospheric Chemistry ◽  
Boreal Forests ◽  
Cloud Condensation Nuclei ◽  
Particle Formation ◽  
Climate System ◽  
Atmospheric Composition ◽  
Cloud Formation ◽  
Aerosol Composition ◽  
The Tropics

&lt;p&gt;We, together with 50 of our colleagues present a review on the interaction between tropical and boreal forests and the atmosphere, especially addressing their influence in the climate system. With its emissions of VOCs, aerosols and trace gases, with strong atmosphere interactions, forests are a key component of the climate system. These emissions and atmospheric processing regulates atmospheric chemistry and are the major source of cloud condensation nuclei (CCN) affecting cloud formation and development, and thus temperature and precipitation. Emissions from forests are thus closely connected to the hydrological and the carbon cycles, being &amp;#160;an essential integrated part of the climate system.&lt;/p&gt;&lt;p&gt;In terms of meteorology, tropical and boreal forests are very different. Temperature, solar radiation, precipitation, evapotranspiration, albedo, cloud structure and cover, convection etc., are all very different. However, the aerosols in the two systems show similarities as Primary Biological Aerosol Particles are the major component (70%) of coarse mode particles in Amazonia while Secondary Organic Aerosol in the tropics are mainly isoprene driven giving a slightly more hygroscopic SOA than the boreal monoterpene driven SOA. The organics constitutes 70 to 85% of PM1 mass for both boreal and tropical forests. In Amazonia, sulfates, nitrates and BC shows very low concentrations, while the boreal sites shows 2-3 times higher concentrations. The Siberian continental site and Amazonian site show remarkable similarities in the lack of new particle formation (NPF) which will be &amp;#160;discussed.&lt;/p&gt;&lt;p&gt;In the tropics dry season and boreal spring and early summer, increasing biomass burning emissions in both forest types dominates the aerosol composition, with high OC and BC concentrations while anthropogenic pollution influences boreal forest atmospheric composition during wintertime. The changes in diffuse to direct radiation due to scattering aerosols has important effects in tropical forests but minor in boreal, enhancing the net ecosystem exchange by 30% and 10% respectively. Thus the natural forest emissions affects the direct as well as the indirect forcing.&lt;/p&gt;&lt;p&gt;An Amazonia high altitude NPF process chain was recently observed at the top of the troposphere, and is an interesting interaction between forest emissions, cloud transport and processing and particle formation and aging at high altitudes that are brought back to the boundary layer, populating the CCN. For boreal forests, the complex relationship between GPP, BVOC, SOA, CCN, clouds, radiation, temperature and CO&lt;sub&gt;2&lt;/sub&gt; show multiple pathways and feedbacks, and some of them can be quantified. All showing the complexity of the interaction between forests, atmosphere and climate.&lt;/p&gt;

scholarly journals Mesosphere-to-stratosphere descent of odd nitrogen in February–March 2009 after sudden stratospheric warming

2011 ◽  
Vol 11 (10) ◽  
pp. 4645-4655 ◽  
Author(s):  
S.-M. Salmi ◽  
P. T. Verronen ◽  
L. Thölix ◽  
E. Kyrölä ◽  
L. Backman ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Transport Model ◽  
Atmospheric Transport ◽  
Polar Vortex ◽  
Polar Regions ◽  
Stratospheric Warming ◽  
Sudden Stratospheric Warming ◽  
Good Opportunity ◽  
Catalytic Ozone Destruction ◽  
Odd Nitrogen

Abstract. We use the 3-D FinROSE chemistry transport model (CTM) and Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) observations to study connections between atmospheric dynamics and middle atmospheric NOx (NOx = NO + NO2) distribution. Two cases are considered in the northern polar regions: (1) descent of mesospheric NOx in February–March 2009 after a major sudden stratospheric warming (SSW) and, for comparison, (2) early 2007 when no NOx descent occurred. The model uses the European Centre for Medium-Range Weather Forecasts (ECMWF) operational data for winds and temperature, and we force NOx at the model upper altitude boundary (80 km) with ACE-FTS observations. We then compare the model results with ACE-FTS observations at lower altitudes. For the periods studied, geomagnetic indices are low, which indicates absence of local NOx production by particle precipitation. This gives us a good opportunity to study effects of atmospheric transport on polar NOx. The model results show no NOx descent in 2007, in agreement with ACE-FTS. In contrast, a large amount of NOx descends in February–March 2009 from the upper to lower mesosphere at latitudes larger than 60° N, i.e. inside the polar vortex. Both observations and model results suggest NOx increases of 150–200 ppb (i.e. by factor of 50) at 65 km due to the descent. However, the model underestimates the amount of NOx around 55 km by 40–60 ppb. According to the model results, chemical loss of NOx is insignificant during the descent period, i.e. polar NOx is mainly controlled by dynamics. The descent is terminated and the polar NOx amounts return to pre-descent levels in mid-March, when the polar vortex breaks. The break-up prevents the descending NOx from reaching the upper stratosphere, where it could participate in catalytic ozone destruction. Both ACE-FTS observations and FinROSE show a decrease of ozone of 20–30 % at 30–50 km from mid-February to mid-March. In the model, these ozone changes are not related to the descent but are due to solar activation of halogen and NOx chemistry.

scholarly journals Particle concentration and flux dynamics in the atmospheric boundary layer as the indicator of formation mechanism

2010 ◽  
Vol 10 (8) ◽  
pp. 20005-20033
Author(s):  
J. Lauros ◽  
A. Sogachev ◽  
S. Smolander ◽  
H. Vuollekoski ◽  
S.-L. Sihto ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Formation Mechanism ◽  
Turbulent Transport ◽  
Particle Formation ◽  
Formation Mechanisms ◽  
Forest Site ◽  
Aerosol Formation ◽  
Flux Dynamics ◽  
Layer Deposition

Abstract. We carried out column model simulations to study particle fluxes and deposition and to evaluate different particle formation mechanisms at a boreal forest site in Finland. We show that kinetic nucleation of sulphuric acid cannot be responsible for new particle formation alone as the vertical profile of particle number distribution does not correspond to observations. Instead organic induced nucleation leads to good agreement confirming the relevance of the aerosol formation mechanism including organic compounds emitted by biosphere. Simulation of aerosol concentration inside the atmospheric boundary layer during nucleation days shows highly dynamical picture, where particle formation is coupled with chemistry and turbulent transport. We have demonstrated suitability of our turbulent mixing scheme in reproducing most important characteristics of particle dynamics inside the atmospheric boundary layer. Deposition and particle flux simulations show that deposition affects noticeably only the smallest particles at the lowest part of the atmospheric boundary layer.

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